01.10.13 9:45 AM ET

It’s the rare head of wardrobe for a television show—particularly a show about young women living in post–Sex and the City New York—who would insist that if she does her job right, “no one should notice the clothes.”

But that’s exactly how Jennifer Rogien approaches her job dressing the girls of Girls, Lena Dunham’s tart, perceptive HBO comedy—which returns for a second season Sunday—about coming of age in an economy where even the most profligate New York fashionistas might consider cutting back on their Louboutin budgets.

Where Sex and the City—a show that informs, but doesn’t directly inspire Girls—gave its characters, women in their late 30s, dream wardrobes, both Rogien and Dunham say that it’s important that the characters be realistic, both in considering where they could actually shop and how they would treat clothes when they purchase them.

“We joke amongst ourselves that Marnie probably lives at Lord & Taylor and Bloomingdale’s, while Shoshanna is a mix between Saks and H&M and Zara. We love that Shoshanna wears Shoshanna,” Rogien tells The Daily Beast. “Jessa is clearly a world traveler so she collects things ... Hannah, being so vintage-driven, none of that is shot for editorial, so it was Etsy girls, and style blogs, and [I] pulled some stuff from Madewell and Anthropologie.”

Those last two stores, according to Rogien, were places where Dunham’s Hannah would save up to buy special pieces. But for her everyday clothes, Rogien shopped at Williamsburg stores like Atlantis Attic, Beacon’s Closet, and Manhattan-based Stella Dallas.

In a March interview before the show’s first season aired, Dunham said that she was attentive to the limitations Hannah would face in fitting the clothes she could afford to her body. “We fit the clothes with Spanx, and then I didn’t wear the Spanx for the show, so everything fits slightly wrong, it tugs a little bit,” she said. “You don’t tailor your thing from the Urban Outfitters sale rack.” In part that’s because “Hannah doesn’t really know that much about clothing,” said Rogien. And she doesn’t always know what she wants to express. “Sometimes the way she’ll put together an outfit or the jewelry she wears, it’s like, ‘Come on!’” Dunham said. “She always has one too many accessories, or an unflattering waistline.”

Experimenting with clothes is one way the characters on Girls play with their identities, but it’s hardly the only one, or even the most important, considering how early the women are in their careers and how much they’re learning about relationships. Their sex lives, in particular, have posed Rogien with some special challenges. Because Girls is a show where how the characters’ clothes come off is as important as what they convey when they’re being worn, Rogien says she spends a lot of time thinking about how clothes are handled and fastened. For a first-season episode where Shoshanna, the sexually inexperienced college student played by Zosia Mamet, hopes to have sex with a date, Rogien and her assistants looked for dresses that opened down the front so Shoshanna’s potential partner could help her undress easily.

“Sometimes you want the magic, you want the clothes to fall off effortlessly, and it’s intimate all of a sudden,” she says. “With Hannah, we want the clothes to come off over the head and to be awkward and uncomfortable,” as it was in a memorable scene in the show’s pilot, where Hannah tried to take off her tights and underwear without getting up from the couch where she had been lying face down.

In the second season, the character’s wardrobes reflect their new experiences, sexual and otherwise, and a dichotomy that Rogien says is important to the show. “There are sort of two, and this is incredibly reductive, two threads: the people who really have an identity, visually, in their young 20s, and the people who are exploring their identities,” she explains. “Hannah and Jessa (Jemima Kirke) are very much exploring, and Marnie (Allison Williams) and Shoshanna have a very clear idea of how they want to express themselves.”

Shoshanna lost her virginity to Ray in the season finale, an experience she later explains in the second season as being a major threshold. “We talked about how do we maybe grow her up a little bit to reflect where she is in her life, so we tweaked her color palette”—which had initially been meant to evoke girlish color-palette cosmetics, like blushes and eye shadows, writ large—“and added a heel here and there,” said Rogien. As befits Shoshanna’s deadly-serious approach to her wardrobe, when she decides to grow up, she goes all in. In an early episode of Girls’ second season, Shoshanna arrives at a party, hosted by Hannah and Elijah (Andrew Rannells) to celebrate his move into Marnie’s old room, wearing a cool blue dress and a fascinator, only to end up making out with T-shirt wearer Ray (Alex Karpovsky), whose definition of adulthood doesn’t seem to include purging souvenirs from summer camp from his wardrobe.

Williams’s Marnie, who spent much of the first season in polished single-color dresses and with her hair up in sleek ponytails, a reflection of her status as the only main character with a steady job, finally let her hair down in crimped waves at Jessa’s wedding in the season finale. “That whole look was about her having really gone through a rough patch and her finding a little bit of peace with it, embracing that it’s not perfect all the time, and it’s OK to let your hair down and wear a pattern and a deep V and a long dress,” says Rogien.

And this season, Marnie confronts the idea that her carefully composed image and approach to her relationships haven’t served her as well as she might like. In an interview for a job at a different gallery after she is laid off, Marnie’s interviewer, pretending to compliment her style, asks where someone might find a suit like the one she chose to wear. “Ann Taylor!” Marnie explains brightly, initially missing the implication that she’s too conservative to succeed in the art world. But that doesn’t mean she’s ready to embrace avant-garde fashion either. At an awkward dinner with ex-boyfriend Charlie (Christopher Abbott) and his new girlfriend, the “tiny Navajo” hipster of the first season, at Hannah’s apartment, Marnie whips out some snark of her own, asking where the other woman buys her trademark headbands. And though she still favors the higher-end jeans and fitted T-shirts that were her casual wear in the first season, Rogien says patterns are making a more regular appearance in Marnie’s rotation, and adds, “There are a couple of signature outfits that will come up that are very specific and very un-Marnie.”

While Shoshanna and Marnie go through very conscious transitions in their lives and clothes, Jessa’s and Hannah’s wardrobes continue to reflect their more haphazard approaches to life, Rogien explained. Hannah wears an uncharacteristically tailored dress with a full skirt to a party, mixing a punch that’s a decided upgrade from the opium tea Ray brought as a hostess gift in the Girls pilot. It’s a reflection of her optimism for living with Elijah, who may not have a bed of his own, but has lots of ideas for theme nights and an older boyfriend who’s covering his half of the rent. But the dress doesn’t last—she shucks it to take care of Adam (Adam Driver), who is still recovering from the accident that took him out at the end of the first season. And she’s still making bad fashion and life decisions simultaneously, changing into a see-through yellow mesh shirt while braless on a dance floor and apocalyptically high on cocaine—all to satisfy the editor at an online magazine.

And “Jessa keeps being Jessa,” Rogien says, “which means that it will both be the same and completely different.” Marrying Thomas Jonathan (Chris O’Dowd), the most boring man in the world, means Jessa has acquired a honeymoon tattoo and a place to sleep that isn’t Shoshanna’s couch. As a married woman, she seems to have moved beyond sheer dresses as baby-sitting uniforms and feathered vests (a replica of a vintage dress owned by actress Jemima Kirke that Rogien re-created so it wouldn’t be damaged during shooting) as club wear. But that doesn’t mean she knows what to wear to dinner with Thomas Jonathan’s parents to convince them that she’s not a gold digger—a pink velvet dress and an enormous chain don’t seem to do the trick, particularly with his mother—or that dropping out of school to spend time in rehab isn’t first-meeting-conversation material.

These fluctuations and uncertainties—and a match between the setting for Girls and the life stages of its characters—contribute to the ephemeral charms of the show’s style. Rogien lives in Brooklyn and did the noir-inspired wardrobes for another show set in her borough, the HBO sitcom Bored to Death.

“The thing that’s great about Brooklyn [is] that as soon as you think you’ve captured it, it’s moved on,” she says. Much like the girls of Girls.